Forward link frame generation in a machine-to-machine (M2M) wireless wide area network (WAN)

ABSTRACT

Methods, systems, and devices are described for managing wireless communications in a machine-to-machine (M2M) wireless Wide Area Network (WAN). A physical layer frame is generated. The frame being used for wireless M2M communications on a forward link in the M2M wireless WAN. The frame including no more than three channels. The physical layer frame including a first channel including paging channel, a second channel including a traffic channel, and a third channel including an acknowledgment (ACK) channel. A time division multiplexing (TDM) operation is performed on pilot symbols and data symbols to obtain a TDM pilot burst. At least one TDM pilot burst is inserted into each channel of the physical layer frame. The physical layer frame is transmitted on the forward link at a low data rate.

BACKGROUND

The following relates generally to wireless communication, and morespecifically to communications in a machine-to-machine (M2M) wirelesswide area network (WAN). Wireless communications systems are widelydeployed to provide various types of communication content such asvoice, video, packet data, messaging, broadcast, sensor data, trackingdata, and so on. These systems may be multiple-access systems capable ofsupporting communication with multiple users by sharing the availablesystem resources (e.g., time, frequency, and power). Examples of suchmultiple-access systems include code-division multiple access (CDMA)systems, time-division multiple access (TDMA) systems,frequency-division multiple access (FDMA) systems, and orthogonalfrequency-division multiple access (OFDMA) systems.

Generally, a wireless multiple-access communications system may includea number of base stations, each simultaneously supporting communicationfor multiple devices. In some examples, these devices may be sensorsand/or meters configured to collect data about other devices andtransmit this data to an end server via a base station. These sensorsand/or meters may be referred to as M2M devices. Base stations maycommunicate with M2M devices on forward and reverse links. Each basestation has a coverage range, which may be referred to as the coveragearea of the cell. A base station may transmit information using a numberof channels within a frame. An M2M device may monitor channels withinmultiple frames to identify data or messages transmitted from the basestation. Because the base station transmits to a number of M2M devices,an M2M device may unnecessarily monitor channels that do not carry dataor messages for that particular device. As a result, the M2M device mayconsume a high level of power monitoring communications transmitted fromthe base station that do not include data or messages intended for thatM2M device.

SUMMARY

The described features generally relate to one or more improved systems,methods, and/or apparatuses for generating forward link frames that areslotted for a number of M2M devices. The structure of the frame mayallow an M2M device to wake up and monitor only the time slots of aframe that include data and/or messages intended for that device andthen return to a sleep state to conserve power.

A method for wireless communication in a machine-to-machine (M2M)wireless Wide Area Network (WAN) is described. In one configuration, aphysical layer frame is generated for wireless M2M communication on aforward link in the M2M wireless WAN. The frame including no more thanthree channels including a first channel comprising a paging channel,and a second channel comprising a traffic channel.

The frame may further include a third channel comprising anacknowledgment (ACK) channel. The length of the first channel comprisingthe paging channel and the length of the third channel comprising theACK channel is 5 milliseconds (ms), and the length of the second channelcomprising the traffic channel is 10 ms. In one example, systeminformation and timing information may be transmitted using the firstchannel comprising the paging channel.

A time slot of the physical layer frame that is assigned to an M2Mdevice may be identified. Data may be transmitted during the identifiedtime slot to the M2M device. A plurality of messages may be receivedfrom a plurality of M2M devices. A plurality of acknowledgment (ACK)messages may be generated, and the plurality of ACK messages may begrouped into an ACK packet. The ACK packet comprising the plurality ofACK messages may be transmitted.

In one embodiment, a time division multiplexing (TDM) operation may beperformed on one or more pilot symbols and one or more data symbols toobtain one or more TDM pilot bursts. The one or more TDM pilot busts maybe inserted in one or more channels of the physical layer frame. EachTDM pilot burst may include a length of 56 chips. A chip may be a pseudonoise (PN) code symbol. Consecutive TDM pilot bursts may be spaced by256 chips.

The TDM pilot bursts and the data symbols may be scrambled using a firstpseudo noise (PN) sequence. The first PN sequence may be offset from aPN sequence used to scramble TDM pilot bursts and data symbols of aframe transmitted from a neighbor base station.

The physical layer frame may be transmitted on the forward link to oneor more M2M devices. In one configuration, the physical layer frame maybe transmitted at a data rate of 9.6 bits per second. The length of thephysical layer frame may be 20 milliseconds (ms).

A base station configured for wireless communication in amachine-to-machine (M2M) wireless Wide Area Network (WAN) is alsodescribed. The base station may include a processor and memory inelectronic communication with the processor. Instructions may be storedin the memory. The instructions may be executable by the processor togenerate a physical layer frame for wireless M2M communication on aforward link in the M2M wireless WAN. The frame may include no more thanthree channels including a first channel comprising a paging channel,and a second channel comprising a traffic channel.

An apparatus configured for wireless communication in amachine-to-machine (M2M) wireless Wide Area Network (WAN) is alsodescribed. The apparatus may include means for generating a physicallayer frame for wireless M2M communication on a forward link in the M2Mwireless WAN. The frame may include no more than three channelsincluding a first channel comprising a paging channel, and a secondchannel comprising a traffic channel.

Further, a computer program product for managing wireless communicationin a machine-to-machine (M2M) wireless Wide Area Network (WAN) is alsodescribed. The computer program product includes a non-transitorycomputer-readable medium storing instructions executable by a processorto generate a physical layer frame for wireless M2M communication on aforward link in the M2M wireless WAN. The frame may include no more thanthree channels including a first channel comprising a paging channel,and a second channel comprising a traffic channel.

Further scope of the applicability of the described methods andapparatuses will become apparent from the following detaileddescription, claims, and drawings. The detailed description and specificexamples are given by way of illustration only, since various changesand modifications within the spirit and scope of the description willbecome apparent to those skilled in the art.

BRIEF DESCRIPTION OF THE DRAWINGS

A further understanding of the nature and advantages of the presentinvention may be realized by reference to the following drawings. In theappended figures, similar components or features may have the samereference label. Further, various components of the same type may bedistinguished by following the reference label by a dash and a secondlabel that distinguishes among the similar components. If only the firstreference label is used in the specification, the description isapplicable to any one of the similar components having the same firstreference label irrespective of the second reference label.

FIG. 1 shows a block diagram of a wireless communications system;

FIG. 2 illustrates an example of a wireless communication systemincluding a wireless wide area network (WAN) implementing M2Mcommunications;

FIG. 3A shows a block diagram illustrating one embodiment of a pagingsystem;

FIG. 3B is a block diagram illustrating one embodiment of a wirelesscommunications system;

FIG. 4A is a block diagram illustrating a device for managing forwardlink communications in accordance with various embodiments;

FIG. 4B is a block diagram illustrating one embodiment of a forward linkcommunications module;

FIG. 5A is a block diagram illustrating a device for managing reverselink communications in accordance with various embodiments;

FIG. 5B is a block diagram illustrating one embodiment of a reverse linkcommunications module;

FIG. 6 is a block diagram illustrating a device for managing forwardlink communications in accordance with various embodiments;

FIG. 7 is a block diagram illustrating one embodiment of a forward linkframe;

FIG. 8 is a block diagram illustrating one example of the forward linkframe;

FIG. 9 is a block diagram illustrating one example of the forward linkframe;

FIG. 10 shows a block diagram of a communications system that may beconfigured for generating a forward link frame in accordance withvarious embodiments;

FIG. 11 is a flow chart illustrating one example of a method formanaging forward link communications; and

FIG. 12 is a flow chart illustrating another example of a method formanaging forward link communications.

DETAILED DESCRIPTION

Methods, systems, and devices are described to generate forward linkframes for communications from a base station to a M2M device in awireless M2M WAN. The frames may be slotted for different M2M devices toallow the base station to communicate with multiple M2M devices. Asingle frame may be a repeating data block with no more than three timeslots. Each slot of each frame may be for a logical time divisionmultiplexed (TDM) channel that carries data and/or messages for aparticular M2M device. The channels within a frame may include a pagingchannel (during a paging slot), an acknowledgment (ACK) channel (duringan ACK slot), and a traffic channel (during a traffic slot). In oneexample, the base station may generate multiple frames. The frames maybe joined to form one larger frame. Data and/or messages for multipleM2M devices may be transmitted in the channels of a frame during certainslots. Currently, M2M devices may unnecessarily consume power by wakingup and monitoring the channels of each time slot of each frame for dataand/or messages (i.e., waking up for the entire duration of thetransmission of the larger frame).

The format of each individual forward link frame of the present systemsand methods may allow the M2M device to wake up and only monitorchannels in the time slots of the individual frames that carry dataand/or messages intended for that device. Once the M2M device hasreceived the message and/or data, it may return to a sleep state. As aresult, the format of the forward link frame described herein allows M2Mdevices to remain in a sleep state until data and/or messages intendedfor that device are actually being transmitted from the base station.Thus, the structure of the forward link frame described herein includesa minimal number of time slots and channels in order to provide powerefficiencies for the M2M devices communicating with the base station ina wireless M2M WAN by allowing the M2M devices to only wake up when atime slot of a frame includes data and/or messages for the devices.

The following description provides examples, and is not limiting of thescope, applicability, or configuration set forth in the claims. Changesmay be made in the function and arrangement of elements discussedwithout departing from the spirit and scope of the disclosure. Variousembodiments may omit, substitute, or add various procedures orcomponents as appropriate. For instance, the methods described may beperformed in an order different from that described, and various stepsmay be added, omitted, or combined. Also, features described withrespect to certain embodiments may be combined in other embodiments.

Referring first to FIG. 1, a block diagram illustrates an example of awireless communications system 100. The system 100 includes basestations 105 (or cells), machine-to-machine (M2M) devices 115, a basestation controller 120, and a core network 130 (the controller 120 maybe integrated into the core network 130). The system 100 may supportoperation on multiple carriers (waveform signals of differentfrequencies).

The base stations 105 may wirelessly communicate with the M2M devices115 via a base station antenna (not shown). The base stations 105 maycommunicate with the M2M devices 115 under the control of the basestation controller 120 via multiple carriers. Each of the base station105 sites may provide communication coverage for a respective geographicarea. The coverage area for each base station 105 here is identified as110-a, 110-b, or 110-c. The coverage area for a base station may bedivided into sectors (not shown, but making up only a portion of thecoverage area). The system 100 may include base stations 105 ofdifferent types (e.g., macro, pico, and/or femto base stations). A macrobase station may provide communication coverage for a relatively largegeographic area (e.g., 35 km in radius). A pico base station may providecoverage for a relatively small geographic area (e.g., 10 km in radius),and a femto base station may provide communication coverage for arelatively smaller geographic area (e.g., 1 km in radium). There may beoverlapping coverage areas for different technologies.

The M2M devices 115 may be dispersed throughout the coverage areas 110.Each M2M device 115 may be stationary or mobile. In one configuration,the M2M devices 115 may be able to communicate with different types ofbase stations such as, but not limited to, macro base stations, picobase stations, and femto base stations. The M2M devices 115 may besensors and/or meters that monitor and/or track other devices,environmental conditions, etc. The information collected by the M2Mdevices 115 may be transmitted across a network that includes a basestation 105 to a back-end system, such as a server. The transmission ofdata to/from the M2M devices 115 may be routed through the base stations105. The base stations 105 may communicate with the M2M devices on aforward link. In one configuration, the base stations 105 may generate aforward link frame with a number of channels to carry data and/ormessages to an M2M device 115. In one example, each forward link framemay include no more than three channels. These channels may include apaging channel, an ACK channel, and a traffic channel. The length of anindividual frame may be short (e.g., 20 milliseconds (ms)). In oneembodiment, four frames may be joined to form a larger frame with aduration of 80 ms. Each frame included in the larger frame may includeno more than three channels such as the paging channel, the ACK channel,and the traffic channel. The paging and ACK channels of each frame mayhave a length of 5 ms while the traffic channel of each frame may have alength of 10 ms. An M2M device 115 may wake up and monitor only theindividual frames (within the larger frame) that include data and/ormessages on its channels that are intended for that M2M device 115.

In one embodiment, M2M devices 115 may be incorporated in other devicesor the M2M devices 115 may be standalone devices. For example, devicessuch as cellular phones and wireless communications devices, personaldigital assistants (PDAs), other handheld devices, netbooks, notebookcomputers, surveillance cameras, handled medical scanning devices, homeappliances, etc. may include one or more M2M devices 115.

In one example, the network controller 120 may be coupled to a set ofbase stations 105 and provide coordination and control for these basestations 105. The controller 120 may communicate with the base stations105 via a backhaul (e.g., core network 125). The base stations 105 mayalso communicate with one another directly or indirectly and/or viawireless or wireline backhaul.

FIG. 2 illustrates an example of a wireless communication system 200including a wireless wide area network (WAN) 205 implementing an M2Mservice according to one aspect. The system 200 may include a number ofM2M devices 115-a and an M2M server 210. Communications between theserver 210 and M2M devices 115 may be routed through a base station 105,that may be considered part of the WAN 205. The base station 105-a maybe an example of the base stations illustrated in FIG. 1. The M2Mdevices 115-a may be examples of the M2M devices 115 illustrated inFIG. 1. One skilled in the art would understand that the quantity of M2Mdevices 115-a, WANs 205, and M2M servers 210 shown in FIG. 2 is forillustration purposes only and should not be construed as limiting.

The wireless communication system 200 may be operable to facilitate M2Mcommunications. M2M communications may include communications betweenone or more devices without human intervention. In one example, M2Mcommunications may include the automated exchange of data between aremote machine, such as an M2M device 115-a, and a back-end ITinfrastructure, such as the M2M server 210, without user intervention.The transfer of data from an M2M device 115-a to the M2M server 210 viathe WAN 205 (e.g., the base station 105-a) may be performed usingreverse link communications. Data collected by the M2M devices 115-a(e.g., monitoring data, sensor data, meter data, etc.) may betransferred to the M2M server 210 on the reverse link communications.

The transfer of data from the M2M server 210 to an M2M device 115-a viathe base station 105-a may be performed via forward link communications.The forward link may be used to send instructions, software updates,and/or messages to the M2M devices 115-a. The instructions may instructthe M2M devices 115-a to remotely monitor equipment, environmentalconditions, etc. M2M communications may be used with variousapplications such as, but not limited to, remote monitoring, measurementand condition recording, fleet management and asset tracking, in-fielddata collection, distribution, and storage, etc. The base station 105-amay generate one or more forward link frames with a small number ofchannels to transmit instructions, software updates, and/or messages.The various M2M devices 115-a may wake up to monitor a specific framewhen instructions or other data is included on a channel of that frame.

In one configuration, different types of M2M communications may beproposed in different wireless access networks that use differentaddressing formats. Different addressing formats may lead to differenttypes of M2M devices 115-a being used for different services. In oneaspect, an M2M network may be implemented which may maintain the M2Mdevices 115-a independent of the WAN technology that is used tocommunicate with the M2M server 210. In such an aspect, the M2M devices115-a and the M2M server 210 may be made independent of the WANtechnology that is used. As a result, a WAN technology used for backhaulcommunication may be replaced with a different WAN technology, withoutaffecting the M2M devices 115-a that may already be installed. Forexample, the M2M server 210 and an M2M device 115-a may communicate witheach other irrespective of the addressing format used by the WANtechnology since the addressing format used by the M2M device 115-a maynot be tied with the addressing used by the implemented WAN technology.

In one embodiment, the behavior of the M2M devices 115-a may bepre-defined. For example, the day, time, etc. to monitor another deviceand transmit the collected information may be pre-defined for an M2Mdevice 115-a. For example, the M2M device 115-a-1 may be programmed tobegin monitoring another device and collect information about that otherdevice at a first pre-defined time period. The device 115-a-1 may alsobe programmed to transmit the collected information at a secondpre-defined time period. The behavior of an M2M device 115-a may beremotely programmed to the device 115-a.

FIG. 3A is a block diagram illustrating one embodiment of a pagingsystem 300 including a base station 105-b and an M2M device 115-b. Thebase station 105-b may be an example of the base stations 105 of FIG. 1or 2. The M2M device 115-b may be an example of the M2M devices 115 ofFIG. 1 or 2.

In a wireless communication system, such as the systems of FIG. 1 or 2,the notions of sleep state and paging are important to provide networkconnectivity to a large population of devices (e.g., M2M devices 115) ina battery power and air link resource efficient manner. A sleep statemay provide the M2M device 115-b with a mode of operation to minimizebattery power consumption by shutting down the whole or a part of thedevices' transmit/receive circuitry. In addition, an M2M device in thesleep state may not be allocated any dedicated air link resource andtherefore a large number of M2M devices may be simultaneously supported.During time intervals where the M2M device 115-b has no trafficactivity, the device 115-b may remain in the sleep state to conserveresources.

Paging may involve the M2M device 115-b waking up periodically from thesleep state, and having the M2M device 115-b operate to receive andprocess a paging message 305 in the forward link communications (e.g.,communications from the base station 105-b to the M2M device 115-b). Thebase station 105-b may be aware when the M2M device 115-b should wakeup. Thus, if the base station 105-b intends to contact, or page, the M2Mdevice 115-b, the base station 105-b may send the paging message 305 ina paging channel of a forward link frame at the time when the M2M device305 is scheduled to wake up and monitor the paging channel. If the basestation 105-b does not receive a paging response 310 confirming that theM2M device 115-b has received the paging message, the base station 105-bmay retransmit the paging message 305 on the paging channel morefrequently. The base station 105-b may retransmit the paging message 305until either the M2M device 115-b receives the paging message 305 andtransmits a paging response 310 and/or a certain number of transmissionsof the paging message 305 has occurred.

In one configuration, the base station 105-b may transmit pagingmessages 305 using one or more sub-channels of the paging channel. Forexample, the base station 105-b may transmit a first paging message on afirst sub-paging channel at a first paging cycle. The base station 105-bmay also transmit a second paging message on a second sub-paging channelat a second paging cycle. In some instances, the first paging messageand the second paging message may be the same (e.g., the paging message305). In addition, the first and second sub-paging channels may also bethe same. In one embodiment, the paging message 305 may be transmittedon the second sub-channel more frequently than the frequency oftransmissions that occurred on the first sub-paging channel.

The time interval between two successive wake-up periods of an M2Mdevice 115-b may be referred to as a paging cycle. The M2M device 115-bmay operate in a sleep state during the portion of the paging cycle whenthe M2M device 115-b is not performing processing related to receiving apaging message 305. In order to maximize the benefit of the sleep state,the paging system 300 may use a large value for the paging cycle. Forexample, in a data system, the paging cycle may be about 5 seconds. Asmentioned above, if the base station 105-b does not receive the pagingresponse 310 indicating the successful receipt of the paging message305, the base station 105-b may retransmit the paging message 305 usinga smaller paging cycle until the paging response 310 is received. Theretransmission of the paging message 305 may occur using the samechannel or a different channel.

Upon receiving the paging message 305, the M2M device 115-b may carryout any operations specified in the paging message 305. For example, theM2M device 115-b may just receive the paging message 305 and go back tothe sleep state. Alternatively, the M2M device 115-b may access the basestation 105-b to establish an active connection with the base station105-b.

FIG. 3B is a block diagram illustrating one embodiment of a wirelesscommunications system 320. The system 320 may include a base station105-c and an M2M device 115-c. The base station 105-c and the M2M device115-c may be examples of the base stations and M2M devices of FIG. 1, 2,or 3A. In one configuration, the base station 105-c may communicate withthe M2M device 115-c using a forward link frame with a limited number ofchannels for forward link communications 325. The M2M device 115-c maycommunicate with the base station 105-c using reverse linkcommunications 330. Communications that occur using the forward andreverse link communications may be M2M communications, as describedabove. These communications may take various forms, dependingprincipally on the air interface protocol used by the base station 105-cand the M2M device 115-c.

The base station 115-c may be arranged to communicate on one or morecarrier frequencies, typically using a pair of frequency bands to definethe forward and reverse links communications, respectively. The basestation 115-c may also include a set of directional antenna elementsarranged to define multiple cell sectors. M2M communications in eachsector on a given carrier frequency may be distinguished fromcommunications in other sectors by modulating the communications in thegiven sector with a sector-specific code, such as a pseudo-random noiseoffset (“PN offset”). Further, M2M communications in each sector may bedivided into control and traffic channels, each of which may be definedthrough time division multiplexing (TDM).

In one embodiment, signals may be transmitted on the forward linkcommunications 325 and the reverse link communications 330 in a frameformat. Within the frame format, information may be packetized andformatted according to the actual payload data to be communicated overthe communication links 325, 330. In one configuration, the format of aframe transmitted on the forward link communications 325 may includevarious channels. In one embodiment, the frame may include the pagingchannel, the ACK channel, and the traffic channel. As mentioned above,the paging channel may be used to transmit paging messages 305 and/orsystem information to the M2M device 115-c. The ACK channel may be usedto transmit an ACK message to an M2M device when a signal issuccessfully received at the base station 105-c. The traffic channel maybe used to transmit data to the M2M device 115-c. Frames used on theforward link communications 325 in M2M communications may be based on ashort duty cycle.

To conserver power, an M2M device 115 may wake up only during specificchannels of specific forward link frames to receive data, pagingmessages 305, etc. As a result, the frame structure in M2Mcommunications may be slotted for each M2M device. For example, a firstframe may include a first paging slot (or first paging channel) thatcarries data intended for a first M2M device 115. A second, third, andfourth frame may include a second, third, and fourth paging slot,respectively. A second, third, and fourth M2M device may receive data onthese slots, respectively. In one embodiment, the M2M device 115-c mayuse a set of hashing functions on its identification (ID), on the numberof slots at the expected data rate, and on a total number of users atthe expected data rate to determine the slot where the device 115-c canexpect to receive its data. Thus, each device 115 may only be requiredto wake up for the slot or channel of the frame that is needed toretrieve its data. As a result, battery power of the M2M devices 115 andair interface resources in the wireless M2M WAN may be conserved.

In one configuration, to preserve communication resources, the M2Mdevice 115-c may perform opportunistic decoding of a message transmittedfrom the base station 105-c in order to return to the sleep state,according to the present systems and methods. In one embodiment, thebase station 105-c may generate one or more forward link frames andtransmit multiple copies of a message to the M2M device 115-c using achannel of the one or more forward link frames. Each copy of the messagemay be sent in a sub-channel of the channel of the frames at a high datarate. The M2M device 115-c may read as many copies of the message as areneeded to successfully demodulate the message. In one configuration, theM2M device 115-c may estimate the number of copies of the message itneeds to receive to decode the message based on the received signalstrength from a pilot signal transmitted from the base station 105-c.Upon successfully decoding the message, the device 115-c may return to asleep state before generating and transmitting an ACK message back tothe base station 105-c. If additional copies of the message remain inthe sub-channels, the base station 105-c may continue to transmit theadditional copies. In one configuration, the device 115-c may conservebattery power by not transmitting an ACK message to the base stationindicating that the message has been received.

In one embodiment, the reverse link communications 330 may be terminatedearly to conserve the battery power of the M2M device 115-c and airinterface resources between the M2M device 115-c and the base station105-c. As stated above, a forward link frame may include an ACK channel.The base station 105-c may use the ACK channel to acknowledge thereception of a reverse link physical layer packet sent from the M2Mdevice 115-c using the reverse link communications 330. In oneconfiguration, ACKs corresponding to higher reverse link data rates maybe transmitted at higher forward link data rate from the base station105-c to the M2M device 115-c. ACKs corresponding to lower reverse linkdata rates may be transmitted at lower forward link data rates. As aresult, rather than sending each ACK at the lowest data rate, it may besent at two different data rates, resulting in two different packetformats. When ACKs are transmitted at higher data rates to the M2Mdevice 115-c, the device 115-c may receive and decode the ACK morequickly, thus terminating the reverse link communications 330 at anearlier time period than if the ACK was transmitted using a low datarate.

In one configuration, the operating band of the reverse linkcommunications 330 may be divided into multiple reverse link frequencychannels. Within each frequency channel, CDMA techniques may be used tomultiplex the reverse link communications for multiple M2M devices 115.In one example, each reverse link frequency channel may have its ownrise over thermal (ROT) operation point. At least one frequency channelmay be dedicated as a low data rate random access channel. Dividing theoperating band of the reverse link communications 330 may provide a lowROT operation target (e.g., 1 decibel (dB) or less) for reverse linkcommunications. A low ROT may reduce the link budget requirement forthose devices in locations with large path loss.

In one example, to increase the power efficiency of the M2M device115-c, a narrowband frequency-division multiple access (FDMA) techniquemay be used for the reverse link communications 330. This technique mayinclude dividing the operating band of the reverse link communications330 into a number of narrowband frequency channels. The base station105-c may broadcast the status and assignment of each narrowband channelto each M2M device 115. The status may be “busy” or “idle”. In oneembodiment, the M2M device 115-c may only transmit data if a narrowbandfrequency channel is assigned to the device 115-c. The early terminationof the reverse link communications 330 (described above) may beincorporated into the narrowband FDMA technique to exploit thesignal-to-interference noise ratio (SINR) distribution and to supportmultiple data rates in the reverse link communications 330.

Turning next to FIG. 4A, a block diagram illustrates a device 400 formanaging forward link communications in accordance with variousembodiments. The device 400 may be an example of one or more aspects ofbase stations 105 described with reference to FIGS. 1, 2, 3A, and/or 3B.The device 400 may also be a processor. The device 400 may include areceiver module 405, a forward link communications module 410, and/or atransmitter module 415. Each of these components may be in communicationwith each other.

These components of the device 400 may, individually or collectively, beimplemented with one or more application-specific integrated circuits(ASICs) adapted to perform some or all of the applicable functions inhardware. Alternatively, the functions may be performed by one or moreother processing units (or cores), on one or more integrated circuits.In other embodiments, other types of integrated circuits may be used(e.g., Structured/Platform ASICs, Field Programmable Gate Arrays(FPGAs), and other Semi-Custom ICs), which may be programmed in anymanner known in the art. The functions of each unit may also beimplemented, in whole or in part, with instructions embodied in amemory, formatted to be executed by one or more general orapplication-specific processors.

The receiver module 405 may receive information such as packet, data,and/or signaling information regarding what the device 400 has receivedor transmitted. The received information may be utilized by the forwardlink communications module 410 for a variety of purposes.

The receiver module 405 may be configured to receive a reverse linkphysical layer packet sent from an M2M device 115 using reverse linkcommunications 330. The receiver module 405 may also be configured toreceive instructions, a set of operations, messages, etc. from aback-end server to communicate to an M2M device 115. The forward linkcommunications module 410 may generate one or more forward link frames.The frames may be short duty cycle frames that include a minimal numberof channels and are slotted for communications with multiple M2Mdevices. Details regarding the generation of the forward link frame willbe described below.

The forward link communications module 410 may generate an ACK messageindicating a packet has been successfully received on the reverse link330. The transmitter module 415 may be configured to transmit the ACKmessage in the forward link frame to the M2M device 115. Instead oftransmitting the ACK channel in the forward link frame at the lowestdata rate, it may be transmitted at a higher data rate, resulting in anincrease in the forward link ACK throughput and early termination ofcommunications received on the reverse link 330 by the receiver 405, aspreviously described.

In one embodiment, the forward link communications module 410 maygenerate a paging message 305 to transmit to an M2M device 115 via thetransmitter module 415. The paging message 305 may alert the M2M device115 that data intended for the device 115 is available on the trafficchannel of the forward link frame. The receiver module 405 may receive apaging response 310 when the M2M device 115 successfully receives thepaging message 305. When the receiver module 405 does not receive thepaging response 310, the forward link communications module 410 may beconfigured to instruct the transmitter module 415 to retransmit thepaging message 305. The transmitter module 415 may retransmit themessage 305 at a higher frequency than the original transmission of thepaging message 305. The transmitter module 415 may cease theretransmission when a paging response 310 is received by the receivermodule 405 and/or after a certain number of retransmissions of themessage 305 have been transmitted. The transmitter module 415 maytransmit and retransmit the paging messages 305 on the same pagingchannel or different paging channels of different forward link frames.In one configuration, when the paging channel is not needed to transmita paging message 305, the forward link communications module 410 maygenerate and insert system information into the paging channel of theforward link frame. The transmitter module 415 may transmit the systeminformation to an M2M device 115 in the paging channel of the frame. Inone configuration, the transmitter 415 may transmit information usingmultiple paging channels of multiple frames. Each paging channel mayhave a different paging cycle.

FIG. 4B is a block diagram illustrating one embodiment of a forward linkcommunications module 410-a. The module 410-a may be an example of theforward link communications module of FIG. 4A. In one example, themodule 410-a may include a forward link frame generating module 420, anACK generating module 425, a paging slot reuse module 430, a pagingcycle selection module 435, a paging channel selection module 440, and ashared traffic channel formatting module 445.

The forward link frame generating module 420 may generate a physicallayer frame to be used for communications on the forward link 325 (e.g.,from a base station to an M2M device). The generated frame may be basedon a short duty cycle and a small number of slotted physical layerchannels. For example, the module 420 may generate a forward linkphysical layer frame that is a total of 20 milliseconds (ms). As aresult, an M2M device 115 may only need to wake up for 20 ms to receivethe forward link frame. Thus, power may be conserved at the M2M device115. The slotted operation of the frame generated by the module 420 mayallow the M2M device 115 to wake up and turn on its radio only duringthe scheduled slot (or channel) of the frame where it is expecting data.

Each of the physical channels of the forward link frame may include bothpilot symbols and data symbols, which may be time division multiplexed(TDM). In one configuration, a forward link frame generated by themodule 420 may include a paging channel (or slot), an ACK channel, and atraffic channel. The paging channel may be used to transmit pagingmessages and other information to an M2M device 115 on the forward linkcommunications 325. The ACK channel may transmit ACK messages andadditional information while the traffic channel may be used to transmitdata messages to an M2M device 115.

The ACK generating module 425 may generate an ACK message to transmit onthe forward link communications 325. The message may be transmitted onan ACK channel that is part of the forward link frame generated by theforward link frame generating module 420. In one configuration, theforward link frame may be used to transmit a compressed identification(ID) to an M2M device 115. The compressed ID may be a hash of thenetwork ID of the M2M device 115. The compressed ID may represent an ACKmessage for the M2M device 115 indicating that the base stationsuccessfully received a packet transmitted from the M2M device on thereverse link. In one configuration, the ACK generating module 425 maygroup the compressed ID for one M2M device together with compressed IDsof other M2M devices to create an ACK packet. ACK packets may includedifferent quantities of compressed IDs. The transmission data rate ofACK packets may fluctuate depending on the number of compressed IDs ineach packet. An ACK packet with a higher number of compressed IDs may betransmitted at a higher data rate than an ACK packet with a lower numberof compressed IDs.

In some instances, a paging slot may be idle for a certain forward linkframe. For example, the paging slot may not be scheduled to transmit apaging message 305 for an M2M device 115. The paging slot reuse module430 may reuse the idle paging slot to communicate system information tothe M2M device 115. The system information may include system timing andsector number information. Thus, the establishment of additionalchannels within the forward link frame to convey the system informationto an M2M device 115 may be avoided. Instead, the paging slot reusemodule 430 may insert the system information in an idle paging slot (orchannel) of the frame.

In one embodiment, the paging cycle selection module 435 may select aparticular paging cycle to transmit paging messages to an M2M device.The module 435 may provide a flexible paging scheme to dynamicallychange the paging cycle for an M2M device 115 in an M2M wireless WAN.The paging cycle selection module 435 may dynamically change the pagingcycle depending on whether a paging response 310 is received from thedevice 115, the time of day, the state of operation of the M2M device115, etc.

In one configuration, the paging channel selection module 440 may selectbetween a primary and secondary paging channel to transmit a pagingmessage to an M2M device 115 using the forward link communications 325.The module 440 may provide a paging scheme that allows for pagingmessages to be transmitted at different paging cycles in an M2M WANusing primary and secondary paging channels. The primary and secondpaging channels may be sub-channels of the paging channel of a frame.The primary paging channel may be used for longer paging cycles whilethe secondary paging channel may be used for shorter paging cycles. Inone example, a base station 105 may transmit a first paging message andthe module 440 may select the primary channel to transmit this messagesince it is to be transmitted at a first paging cycle. The base stationmay also transmit a second paging message and the module 440 may selectthe secondary paging channel to transmit the second paging message sincethe second message is to be transmitted at a second paging cycle. In oneembodiment, the second paging cycle may be shorter than the first pagingcycle.

The shared traffic channel formatting module 445 may format a trafficchannel in the forward link frame that may be shared by multiple M2Mdevices. When a M2M device 115 is expecting data on a shared trafficchannel within a given traffic channel cycle, the device 115 maycontinue reading the traffic channel slots across multiple forward linkframes during a traffic channel cycle until it finds its data asindicated by the ID field. As a result, the M2M device 115 may stayawake longer than necessary to find its data. The formatting module 445may format the traffic channel in such a way so as to minimize the wakeup time for the M2M device 115. The M2M device 115 may determine whichslot of a particular frame to wake up in order to get its data on theshared traffic channel. To determine which slot to wake up for, the M2Mdevice may use a set of hashing function on its ID. The M2M device mayalso use the number of slots at the expected data rate and the totalnumber of users at that rate to determine the slot where it can expectto receive its data. The traffic channel may be formatted by the module445 to allow the device to determine which slot to use. For example, themodule 445 may format the shared traffic channel so that the hashed sloteither contains the data or a pointer to a slot where the actual data islocated. If a slot of a first frame cannot contain all the pointers, themodule 445 may set an overflow flag and provide a pointer to anotherslot of another frame where the hashed M2M device can check for itsdata. If all the data for the M2M device 115 cannot be accommodated intoa single slot, then the module 445 may format a trailer field of thechannel to include a pointer to another slot where the remaining data istransmitted.

FIG. 5A is a block diagram illustrating a device 500 for managingreverse link communications in accordance with various embodiments. Thedevice 500 may be an example of one or more aspects of the M2M device115 described with reference to FIGS. 1, 2, 3A, and/or 3B. The device500 may also be a processor. The device 500 may include a receivermodule 505, a reverse link communications module 510, and/or atransmitter module 515. Each of these components may be in communicationwith each other.

These components of the device 500 may, individually or collectively, beimplemented with one or more application-specific integrated circuits(ASICs) adapted to perform some or all of the applicable functions inhardware. Alternatively, the functions may be performed by one or moreother processing units (or cores), on one or more integrated circuits.In other embodiments, other types of integrated circuits may be used(e.g., Structured/Platform ASICs, Field Programmable Gate Arrays(FPGAs), and other Semi-Custom ICs), which may be programmed in anymanner known in the art. The functions of each unit may also beimplemented, in whole or in part, with instructions embodied in amemory, formatted to be executed by one or more general orapplication-specific processors.

The receiver module 505 may receive information such as packet, data,and/or signaling information regarding what the device 500 has receivedor transmitted. The received information may be utilized by the reverselink communications module 510 for a variety of purposes.

The receiver module 505 may be configured to receive a forward linkphysical layer packet sent from a base station 105 using forward linkcommunications 325. The reverse link communications module 510 maygenerate a reverse link frame that includes a traffic channel totransmit data from an M2M device 115 to a base station 105.

In one embodiment, the reverse link communications module 510 may causecommunications on the reverse link to terminate early. As previouslyexplained, the forward link frame may include an ACK channel to transmitACK messages from the base station 105 to an M2M device 115 at a highdata rate. ACK messages corresponding to higher reverse link data ratesmay be received by the receiver module 505 at the higher data rate. Uponreceiving the ACK message, the reverse link communications module 510may instruct the transmitter 515 to cease transmitting communications onthe reverse link communications 330. Details regarding the reverse linkcommunication module 510 will be described below.

FIG. 5B is a block diagram illustrating one embodiment of a reverse linkcommunications module 510-a. The module 510-a may be an example of thereverse link communications module of FIG. 5A. In one example, themodule 510-a may include a sleep state module 520, a multi-channelmodule 525, and a narrowband multiple access module 530.

In one configuration, the sleep state module 520 may allow an M2M device115 to wake up long enough to receive a message from a base station 105and then return to a sleep state to conserve power. The base station maytransmit a message to the M2M device using a forward link frame. Theframe may include a paging channel to carry the message. The pagingchannel may include a number of sub-channels. The base station maytransmit a copy of the message in each sub-channel. When the M2M devicesuccessfully receives and demodulates the message on one of thesub-channels, the sleep state module 520 may cause the M2M device 115 toturn off its radio and return to a sleep state to conserve the batterywithout sending an ACK message back to the base station.

In one embodiment, the multi-channel module 525 may provide a codedivision multiple access (CDMA) based multiple access scheme to reducenegative effects of an operating rise over thermal (ROT) noise on thereverse link communications 330. In one configuration, the module 525may divide the operating band of the reverse link into multiple reverselink frequency channels. Within each frequency channel, the module 525may use CDMA for multiple user multiplexing. Each frequency channel mayhave its own target ROT operation point. The multi-channel module 525may dedicate at least one frequency channel as a low data rate randomaccess channel. As a result, the operating ROT may be reduced.

In one example, the narrowband multiple access module 530 may provide anarrowband frequency division multiple access (FDMA) technique for thereverse link communications 330. The module 530 may divide the operatingband into a number of narrowband frequency channels. A busy or idlestatus of each narrowband channel may be broadcasted to each M2M device115. The devices may contend for a channel selected randomly from theidle set of channels by sending a preamble. The module 530 may allow theM2M device 115 to transmit data only if a channel is either implicitlyor explicitly assigned to the M2M device. The module 530 may not allowthe transmission to be interrupted if the channel state changes to busy.

FIG. 6 is a block diagram illustrating a device 600 for managing forwardlink communications in accordance with various embodiments. The device600 may be an example of one or more aspects of the base stationdescribed with reference to FIGS. 1, 2, 3A, 3B, 4A, and/or 4B. Thedevice 600 may also be a processor. The device 600 may include areceiver module 405-a, a forward link communications module 410-a,and/or a transmitter module 415-a. Each of these components may be incommunication with each other.

The components of the device 600 may, individually or collectively, beimplemented with one or more application-specific integrated circuits(ASICs) adapted to perform some or all of the applicable functions inhardware. Alternatively, the functions may be performed by one or moreother processing units (or cores), on one or more integrated circuits.In other embodiments, other types of integrated circuits may be used(e.g., Structured/Platform ASICs, Field Programmable Gate Arrays(FPGAs), and other Semi-Custom ICs), which may be programmed in anymanner known in the art. The functions of each unit may also beimplemented, in whole or in part, with instructions embodied in amemory, formatted to be executed by one or more general orapplication-specific processors.

The receiver module 405-a may receive information such as packet, data,and/or signaling information regarding what the device 600 has receivedor transmitted. The received information may be utilized by the forwardlink communications module 410-a for a variety of purposes, aspreviously described.

In one configuration, the forward link communications module 410-a mayinclude a forward link frame generating module 420. The module 420 maygenerate one or more frames used for transmitting communications to anM2M device 115 on the forward link. Details regarding the framegenerated by the forward link frame generating module 420 will bedescribed below.

FIG. 7 is a block diagram illustrating one embodiment of a forward linkframe 700. In one configuration, the frame 700 may be a cyclicallyrepeated data block that includes a fixed number of time slots. Eachtime slot may be for a logical TDM channel. In one example, the forwardlink frame 700 may be generated by the forward link frame generatingmodule 420, described in FIG. 5B and/or FIG. 6. The frame 700 mayinclude a first channel 705 during a first time slot, a second channel710 during second time slot, and a third channel 715 during a third timeslot. Each channel may be used to transmit various types of data to oneor more M2M devices 115. These channels are described in more detailbelow.

As illustrated in FIG. 8, a forward link frame 700-a may include apaging channel 805, an ACK channel 810, and a traffic channel 815. Theforward link frame 700-a may be an example of the frame 700 illustratedin FIG. 7. In one configuration, the frame 700-a may be generated by theforward link frame generating module 420 of FIG. 5B and/or FIG. 6. Theframe 700-a may be generated as a physical layer frame to be transmittedon the forward link communications 325. In one embodiment, multipleframes 700-a may be transmitted. Each frame may include no more thanthree time slots and each time slot may include one channel. Thus, eachforward link frame 700-a may include no more than three logical TDMchannels. The channels of the frame 700-a may include the paging channel805, the ACK channel 810, and the traffic channel 815. In oneconfiguration, each paging slot and ACK slot may have a length of 5 ms.Each traffic slot may have a length of 10 ms. Thus, the paging channel805 and ACK channel 810 may transmit their data for 5 ms each. Thetraffic channel 815 may transmit data for 10 ms. As a result, eachforward link frame 700-a may have a length of 20 ms.

In one embodiment, the base station 105 that transmits the frame 700-aon the forward link communications 325 may transmit a number of frames700-a to a large geographic area (e.g., a radius of approximately 35km). As a result, the base station 105 may transmit each forward linkframe 700-a using a low data rate. For example, a number of forward linkframes 700-a may be transmitted at an effective data rate ofapproximately 9.6 bits/second.

The paging channel 805 may be used to carry paging messages 305 to oneor more M2M devices 115. In one example, the paging channel 805 maytransmit the messages 305 for 5 ms for each frame 700-a. The pagingchannel 805 may also include a number of sub-channels. The sub-channelsmay be used to transmit multiple paging messages 305. Each sub-channelmay transmit a copy of the same message 305, and/or the sub-channels maytransmit different messages. In one configuration, each sub-channel maytransmit the paging messages 305 at different paging cycles.Alternatively, the sub-channels may transmit the messages 305 using thesame paging cycle. In one embodiment, the base station 105 may transmita copy of a paging message 305 using multiple sub-channels. Each copy ofthe message 305 may be transmitted at a high data rate (e.g., 80 kbps).The sleep state module 520 may cause the M2M device 115 to enter thesleep state before transmitting an ACK message back to the base station105 indicating that the device 115 received the paging message 305. As aresult, the base station 105 may continue to transmit copies of thepaging message 305 using the sub-channels of the paging channel 805 eventhough the M2M device 115 has successfully received the message 305.

In one embodiment, the paging channel 805 may be null (i.e., does notinclude a paging message 305). When a null paging channel 805 is presentin the frame 700-a, the paging slot reuse module 430 may use the channel805 to transmit system information to the M2M device 115 during thepaging slot of the frame 700-a. System information may include timinginformation and/or information relating to the sector of the basestation 105 that is communicating the frame 700-a to the M2M device 115.

The ACK channel 810 may be used to transmit an ACK message. The ACKmessage may indicate that the base station 105 has successfully receiveda message from an M2M device 115. In one configuration, the ACKgenerating module 425 may generate the ACK message to be transmitted onthe ACK channel 810. As previously described, the ACK channel 810 maytransmit a compressed ID of the M2M device 115 that represents the ACKmessage. The ACK channel 810 may transmit multiple compressed IDs formultiple M2M devices 115 as an ACK packet. In one configuration, the ACKchannel 810 may transmit ACK packets at different data rates. Forexample, the ACK channel 810 may transmit at a higher data rate when acertain number of compressed IDs are included in the ACK packet. If alesser number of compressed IDs are in the ACK packet, the channel 810may transmit the packet at a lower data rate.

In one example, the traffic channel 815 may transmit a data payload toan M2M device 115. In one embodiment, the channel 815 may transmit datafor multiple M2M devices 115. For example, multiple forward link frames700-a may be transmitted. Each traffic time slot of each frame 700-a maycarry data for a different M2M device 115. The shared traffic channelformatting module 445 may format the traffic channel 815 so that eachM2M device 115 may determine which time slot and frame 700-a is carryingtheir data payload. For example, the module 445 may format the sharedtraffic channel 815 so that a slot either contains the data or a pointerto a slot where the actual data is located. If a slot cannot contain allthe pointers, the module 445 may set an overflow flag and provide apointer to another slot where the M2M device may check for its data. Ifall the data for the M2M device 115 cannot be accommodated into a singleslot, then the module 445 may format a trailer field of the channel toinclude a pointer to another slot where the remaining data may betransmitted.

FIG. 9 is a block diagram illustrating one example of a forward linkframe 700-b. The frame 700-b may be an example of the frame 700 of FIG.7 or 8. The frame 700-b may include three time slots. The first timeslot may be 5 ms and may include a paging channel 805-a. The second timeslot may also be 5 ms and may include an ACK channel 810-a. The thirdtime slot may be 10 ms and may include a traffic channel 815-a.

In one configuration, each channel of the frame 700-b may transmit anumber of TDM pilot signals 905. Each signal 905 may include acombination of pilot symbols and data symbols. The symbols of eachsignal 905 may be multiplexed together using TDM techniques. In oneembodiment, the data and pilot symbol combination transmitted from abase station 105 in a first cell (such as a first cell 110-a,illustrated in FIG. 1) may be scrambled with a pseudo-noise (PN)sequence in order to separate the data/pilot symbol combinations beingtransmitted from a base station in a neighboring cell (such as a secondcell 110-b, illustrated in FIG. 1). The different cells (e.g., 110-a,110-b, 110-c of FIG. 1) may use a different time offset of the same PNsequence as their scrambling code to simplify the initial cell searchperformed by an M2M device 115 as well as reduce the initial acquisitiontime of the device 115. The PN sequence may have a length of 2¹⁴ tocover four forward link frames 700 that have a length of 20 ms each (atotal duration of 80 ms).

In one embodiment, the chip rate of the frame 700-b may be approximately204.8 kilo chips per second (kcps). The chip rate may represent thenumber of pulses per second (chips per second) at which the PN sequenceis transmitted. In one example, each TDM pilot signal 905 may have alength of 56 chips. A spacing 910 may exist between each pilot signal905. The spacing 910 may be 256 chips. In one configuration, signalsfrom different base stations may be covered by the same PN sequence butwith a different initial offset. The different initial offset may bereferred to as PN offset. Using a spacing of 256 chips between pilotsignals 905 of a frame may result in 64 different TDM pilot signals 905.For example, each of the four forward link frames 700-b may include 16TDM pilot signals 905. A TDM pilot group 915 may include four TDM pilotsignals 905. Each TDM pilot group 915 may have a length of 1024 chips.

FIG. 10 shows a block diagram of a communications system 1000 that maybe configured for generating a forward link frame 700 in accordance withvarious embodiments. This system 1000 may be an example of aspects ofthe system 100 depicted in FIG. 1, system 200 of FIG. 2, system 300 ofFIG. 3A, and/or system 320 of FIG. 3B.

The system 1000 may include a base station 105-d. The base station 105-dmay include antennas 1045, a transceiver module 1050, memory 1070, and aprocessor module 1065, which each may be in communication, directly orindirectly, with each other (e.g., over one or more buses). Thetransceiver module 1050 may be configured to communicatebi-directionally, via the antennas 1045, with an M2M device 115, whichmay be a sensor, meter, or any other type of device capable of tracking,sensing, monitoring, etc. The transceiver module 1050 (and/or othercomponents of the base station 105-d) may also be configured tocommunicate bi-directionally with one or more networks. In some cases,the base station 105-d may communicate with the core network 130-aand/or controller 120-a through network communications module 1075.Controller 120-a may be integrated into the base station 105-d in somecases.

Base station 105-d may also communicate with other base stations 105,such as base station 105-m and base station 105-n. Each of the basestations 105 may communicate with the M2M device 115 using differentwireless communications technologies, such as different Radio AccessTechnologies. In some cases, base station 105-d may communicate withother base stations such as 105-m and/or 105-n utilizing base stationcommunication module 1015. In some embodiments, base station 105-d maycommunicate with other base stations through controller 120-a and/orcore network 130-a.

The memory 1070 may include random access memory (RAM) and read-onlymemory (ROM). The memory 1070 may also store computer-readable,computer-executable software code 1071 containing instructions that areconfigured to, when executed, cause the processor module 1065 to performvarious functions described herein (e.g., frame generation, pagingschemes, ACK schemes, data traffic schemes, etc.). Alternatively, thesoftware 1071 may not be directly executable by the processor module1065 but may be configured to cause the computer, e.g., when compiledand executed, to perform functions described herein.

The processor module 1065 may include an intelligent hardware device,e.g., a central processing unit (CPU) such as those made by Intel®Corporation or AMD®, a microcontroller, an application-specificintegrated circuit (ASIC), etc. The transceiver module 1050 may includea modem configured to modulate packets for the M2M device 115 andprovide the modulated packets to the antennas 1045 for transmission, andto demodulate packets received from the antennas 1045. While someexamples of the base station 105-d may include a single antenna 1045,the base station 105-d preferably includes multiple antennas 1045 formultiple links which may support carrier aggregation. For example, oneor more links may be used to support macro communications with the M2Mdevice 115.

According to the architecture of FIG. 10, the base station 105-d mayfurther include a communications management module 1030. Thecommunications management module 1030 may manage communications withother base stations 105. By way of example, the communicationsmanagement module 1030 may be a component of the base station 105-d incommunication with some or all of the other components of the basestation 105-d via a bus. Alternatively, functionality of thecommunications management module 1030 may be implemented as a componentof the transceiver module 1050, as a computer program product, and/or asone or more controller elements of the processor module 1065.

The components for base station 105-d may be configured to implementaspects discussed above with respect to device 400 in FIG. 4A and maynot be repeated here for the sake of brevity. For example, the forwardlink generating module 420-a may be an example of the module 420 ofFIGS. 4A and/or 4B. The module 420-a may include paging informationgenerating module 1055. The module 1055 may generate paging messages 305and other information transmitted on the paging channel 805 as describedin FIG. 3A, 3B, 4A, 4B, 6, 7, 8, or 9. The frame generating module 420-amay also include an ACK information generating module 1060. The module1060 may generate an ACK message and other information to transmit onthe ACK channel 810 as described in FIG. 3B, 4A, 4B, 6, 7, 8, or 9.Further, a traffic information generating module 1065 may be included asa part of the forward link frame generating module 420-a. The module1065 may generate data and additional information to transmit on thetraffic channel 815 in accordance with the present systems and methods.For example, the module 1065 may generate traffic data and otherinformation as described in FIG. 3B, 4A, 4B, 6, 7, 8, or 9.

In some embodiments, the transceiver module 1050 in conjunction withantennas 1045, along with other possible components of base station105-d, may transmit a number of forward link frames 700 that include apaging channel 805, an ACK channel 810, and a traffic channel 815 fromthe base station 105-d to the M2M device 115, to other base stations105-m/105-n, or core network 130-a.

FIG. 11 is a flow chart illustrating one example of a method 1100 formanaging forward link communications. For clarity, the method 1100 isdescribed below with reference to the base station 105 shown in FIG. 1,2, 3A, 3B, 4A, 6, or 10. In one implementation, the forward link framegenerating module 420 may execute one or more sets of codes to controlthe functional elements of the base station 105 to perform the functionsdescribed below.

At block 1105, a physical layer frame may be generated. The frame may befor wireless M2M communication on a forward link. The communications mayoccur in an M2M wireless wide area network (WAN). In one configuration,a single generated frame may include no more than three channels. In oneembodiment, the frame may include a first channel comprising a pagingchannel, and a second channel comprising a traffic channel. The firstchannel may be used to transmit paging messages 305 and otherinformation from the base station 105 to the M2M device 115.

At block 1110, the physical layer frame may be transmitted on theforward link in the M2M wireless WAN. In one embodiment, the basestation 105 may transmit a number of frames. For example, the basestation 105 may transmit a set of four frames on the forward link. Thephysical layer frames may be formatted so that the M2M device 115 wakesup to monitor a specific paging slot of a certain frame to receive apaging message 305 and/or other information transmitted on the pagingchannel. As a result, the M2M device 115 may be in a wake mode toreceive messages and/or information only during a certain time slot.After receiving the message and/or information at the designated slot,the M2M device 115 may return to a sleep state, thus conserving power.

Therefore, the method 1100 may provide for efficient communications onthe forward link. It should be noted that the method 1100 is just oneimplementation and that the operations of the method 1100 may berearranged or otherwise modified such that other implementations arepossible.

FIG. 12 is a flow chart illustrating one example of a method 1200 formanaging forward link communications. For clarity, the method 1200 isdescribed below with reference to the base station 105 shown in FIG. 1,2, 3A, 3B, 4A, 6, or 10. In one implementation, the forward link framegenerating module 420 may execute one or more sets of codes to controlthe functional elements of the base station 105 to perform the functionsdescribed below.

At block 1205, a physical layer for wireless M2M communications on aforward link may be generated. The frame may be used for communicatingin an M2M wireless WAN. In one configuration, the frame may include nomore than three channels. The three channels may include a first channelcomprising a paging channel 805, a second channel comprising a trafficchannel 815, and a third channel comprising an ACK channel 810.

At block 1210, a time division multiplexing (TDM) operation may beperformed on one or more pilot symbols and one or more data symbols toobtain a TDM pilot burst. In one example, one or more TDM pilot burstsmay be included in each channel of the forward link frame. Consecutivepilot bursts in the frame may be separated by a certain number of chips.The TDM pilot bursts may be periodic so that a TDM pilot burst may berepeated every certain number of frames. For example, a TDM pilot burstmay be repeated every fourth forward link frame. At block 1215, the TDMpilot bursts and the data symbols of a frame may be scrambled using a PNsequence. A neighboring base station in a neighboring cell may alsoscramble the TDM pilot bursts and the data symbols using the same PNsequence. The PN sequence used by the neighboring base station, however,may be offset from the PN sequence used to scramble the pilot and dataat block 1215. As a result, pilot bursts transmitted in frames fromdifferent base stations may be offset from one another to allow an M2Mdevice 115 to more easily acquire timing information and other signalsfrom its serving base station 105.

Therefore, the method 1200 may provide for efficient communications onthe forward link by including a TDM pilot burst in each channel of theforward link frame instead of a continuous pilot signal. It should benoted that the method 1200 is just one implementation and that theoperations of the method 1200 may be rearranged or otherwise modifiedsuch that other implementations are possible.

The detailed description set forth above in connection with the appendeddrawings describes exemplary embodiments and does not represent the onlyembodiments that may be implemented or that are within the scope of theclaims. The term “exemplary” used throughout this description means“serving as an example, instance, or illustration,” and not “preferred”or “advantageous over other embodiments.” The detailed descriptionincludes specific details for the purpose of providing an understandingof the described techniques. These techniques, however, may be practicedwithout these specific details. In some instances, well-known structuresand devices are shown in block diagram form in order to avoid obscuringthe concepts of the described embodiments.

Information and signals may be represented using any of a variety ofdifferent technologies and techniques. For example, data, instructions,commands, information, signals, bits, symbols, and chips that may bereferenced throughout the above description may be represented byvoltages, currents, electromagnetic waves, magnetic fields or particles,optical fields or particles, or any combination thereof.

The various illustrative blocks and modules described in connection withthe disclosure herein may be implemented or performed with ageneral-purpose processor, a digital signal processor (DSP), anapplication specific integrated circuit (ASIC), a field programmablegate array (FPGA) or other programmable logic device, discrete gate ortransistor logic, discrete hardware components, or any combinationthereof designed to perform the functions described herein. Ageneral-purpose processor may be a microprocessor, but in thealternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, multiple microprocessors, one or moremicroprocessors in conjunction with a DSP core, or any other suchconfiguration.

The functions described herein may be implemented in hardware, softwareexecuted by a processor, firmware, or any combination thereof. Ifimplemented in software executed by a processor, the functions may bestored on or transmitted over as one or more instructions or code on acomputer-readable medium. Other examples and implementations are withinthe scope and spirit of the disclosure and appended claims. For example,due to the nature of software, functions described above can beimplemented using software executed by a processor, hardware, firmware,hardwiring, or combinations of any of these. Features implementingfunctions may also be physically located at various positions, includingbeing distributed such that portions of functions are implemented atdifferent physical locations. Also, as used herein, including in theclaims, “or” as used in a list of items prefaced by “at least one of”indicates a disjunctive list such that, for example, a list of “at leastone of A, B, or C” means A or B or C or AB or AC or BC or ABC (i.e., Aand B and C).

Computer-readable media includes both computer storage media andcommunication media including any medium that facilitates transfer of acomputer program from one place to another. A storage medium may be anyavailable medium that can be accessed by a general purpose or specialpurpose computer. By way of example, and not limitation,computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or otheroptical disk storage, magnetic disk storage or other magnetic storagedevices, or any other medium that can be used to carry or store desiredprogram code means in the form of instructions or data structures andthat can be accessed by a general-purpose or special-purpose computer,or a general-purpose or special-purpose processor. Also, any connectionis properly termed a computer-readable medium. For example, if thesoftware is transmitted from a website, server, or other remote sourceusing a coaxial cable, fiber optic cable, twisted pair, digitalsubscriber line (DSL), or wireless technologies such as infrared, radio,and microwave, then the coaxial cable, fiber optic cable, twisted pair,DSL, or wireless technologies such as infrared, radio, and microwave areincluded in the definition of medium. Disk and disc, as used herein,include compact disc (CD), laser disc, optical disc, digital versatiledisc (DVD), floppy disk and blu-ray disc where disks usually reproducedata magnetically, while discs reproduce data optically with lasers.Combinations of the above are also included within the scope ofcomputer-readable media.

The previous description of the disclosure is provided to enable aperson skilled in the art to make or use the disclosure. Variousmodifications to the disclosure will be readily apparent to thoseskilled in the art, and the generic principles defined herein may beapplied to other variations without departing from the spirit or scopeof the disclosure. Throughout this disclosure the term “example” or“exemplary” indicates an example or instance and does not imply orrequire any preference for the noted example. Thus, the disclosure isnot to be limited to the examples and designs described herein but is tobe accorded the widest scope consistent with the principles and novelfeatures disclosed herein.

What is claimed is:
 1. A method for wireless communication in amachine-to-machine (M2M) wireless Wide Area Network (WAN), comprising:generating a physical layer frame for wireless M2M communication on aforward link in the M2M wireless WAN, the frame comprising no more thanthree channels including a first channel comprising a paging channel anda second channel comprising a traffic channel; performing a timedivision multiplexing (TDM) operation on one or more pilot symbols andone or more data symbols to obtain one or more TDM pilot bursts;scrambling the TDM pilot bursts and the data symbols using a firstpseudo noise (PN) sequence, the first PN sequence being offset from a PNsequence used to scramble TDM pilot bursts and data symbols of a frametransmitted from a neighbor base station; and inserting the one or moreTDM pilot busts in one or more channels of the physical layer frame. 2.The method of claim 1, wherein the frame further includes a thirdchannel comprising an acknowledgment (ACK) channel, the length of thefirst channel comprising the paging channel and the length of the thirdchannel comprising the ACK channel is 5 milliseconds (ms), and thelength of the second channel comprising the traffic channel is 10 ms. 3.The method of claim 1, further comprising: transmitting systeminformation and timing information using the first channel comprisingthe paging channel.
 4. The method of claim 1, further comprising:identifying a time slot of the physical layer frame that is assigned toan M2M device; and transmitting data during the identified time slot tothe M2M device.
 5. The method of claim 1, further comprising: receivinga plurality of messages from a plurality of M2M devices; generating aplurality of acknowledgment (ACK) messages; grouping the plurality ofACK messages into an ACK packet; and transmitting the ACK packetcomprising the plurality of ACK messages.
 6. The method of claim 1,further comprising: inserting the one or more TDM pilot bursts in eachchannel of the physical layer frame, each TDM pilot burst comprising alength of 56 chips, a chip being a pseudo noise (PN) code symbol; andspacing consecutive TDM pilot bursts by 256 chips.
 7. The method ofclaim 1, further comprising: transmitting the physical layer frame onthe forward link to one or more M2M devices, wherein the physical layerframe is transmitted at a data rate of 6 bits per second.
 8. The methodof claim 1, wherein the length of the physical layer frame is 20milliseconds (ms).
 9. A base station configured for wirelesscommunication in a machine-to-machine (M2M) wireless Wide Area Network(WAN), comprising: a processor; memory in electronic communication withthe processor; and instructions stored in the memory, the instructionsbeing executable by the processor to: generate a physical layer framefor wireless M2M communication on a forward link in the M2M wirelessWAN, the frame comprising no more than three channels including a firstchannel comprising a paging channel, and a second channel comprising atraffic channel; perform a time division multiplexing (TDM) operation onone or more pilot symbols and one or more data symbols to obtain one ormore TDM pilot bursts; scramble the TDM pilot bursts and the datasymbols using a first pseudo noise (PN) sequence, the first PN sequencebeing offset from a PN sequence used to scramble TDM pilot bursts anddata symbols of a frame transmitted from a neighbor base station; andinsert the one or more TDM pilot busts in one or more channels of thephysical layer frame.
 10. The base station of claim 9, wherein the framefurther includes a third channel comprising an acknowledgment (ACK)channel, the length of the first channel comprising the paging channeland the length of the third channel comprising the ACK channel is 5milliseconds (ms), and the length of the second channel comprising thetraffic channel is 10 ms.
 11. The base station of claim 9, wherein theinstructions are further executable by the processor to: transmit systeminformation and timing information using the first channel comprisingthe paging channel.
 12. The base station of claim 9, wherein theinstructions are further executable by the processor to: identify a timeslot of the physical layer frame that is assigned to an M2M device; andtransmit data during the identified time slot to the M2M device.
 13. Thebase station of claim 9, wherein the instructions are further executableby the processor to: receive a plurality of messages from a plurality ofM2M devices; generate a plurality of acknowledgment (ACK) messages;group the plurality of ACK messages into an ACK packet; and transmit theACK packet comprising the plurality of ACK messages.
 14. The basestation of claim 9, wherein the instructions are further executable bythe processor to: insert the one or more TDM pilot bursts in eachchannel of the physical layer frame, each TDM pilot burst comprising alength of 56 chips, a chip being a pseudo noise (PN) code symbol; andspace consecutive TDM pilot bursts by 256 chips.
 15. The base station ofclaim 9, wherein the instructions are further executable by theprocessor to: transmit the physical layer frame on the forward link toone or more M2M devices, wherein the physical layer frame is transmittedat a data rate of 9.6 bits per second.
 16. The base station of claim 9,wherein the length of the physical layer frame is 20 milliseconds (ms).17. An apparatus configured for wireless communication in amachine-to-machine (M2M) wireless Wide Area Network (WAN), comprising:means for generating a physical layer frame for wireless M2Mcommunication on a forward link in the M2M wireless WAN, the framecomprising no more than three channels including a first channelcomprising a paging channel, and a second channel comprising a trafficchannel; means for performing a time division multiplexing (TDM)operation on one or more pilot symbols and one or more data symbols toobtain one or more TDM pilot bursts; means for scrambling the TDM pilotbursts and the data symbols using a first pseudo noise (PN) sequence,the first PN sequence being offset from a PN sequence used to scrambleTDM pilot bursts and data symbols of a frame transmitted from a neighborbase station; and means for inserting the one or more TDM pilot busts inone or more channels of the physical layer frame.
 18. The apparatus ofclaim 17, wherein the frame further includes a third channel comprisingan acknowledgment (ACK) channel, the length of the first channelcomprising the paging channel and the length of the third channelcomprising the ACK channel is 5 milliseconds (ms), and the length of thesecond channel comprising the traffic channel is 10 ms.
 19. Theapparatus of claim 17, further comprising: means for transmitting systeminformation and timing information using the first channel comprisingthe paging channel.
 20. The apparatus of claim 17, further comprising:means for identifying a time slot of the physical layer frame that isassigned to an M2M device; and means for transmitting data during theidentified time slot to the M2M device.
 21. The apparatus of claim 17,further comprising: means for receiving a plurality of messages from aplurality of M2M devices; means for generating a plurality ofacknowledgment (ACK) messages; means for grouping the plurality of ACKmessages into an ACK packet; and means for transmitting the ACK packetcomprising the plurality of ACK messages.
 22. The apparatus of claim 17,further comprising: means for inserting the one or more TDM pilot burstsin each channel of the physical layer frame, each TDM pilot burstcomprising a length of 56 chips, a chip being a pseudo noise (PN) codesymbol; and means for spacing consecutive TDM pilot bursts by 256 chips.23. The apparatus of claim 17, further comprising: means fortransmitting the physical layer frame on the forward link to one or moreM2M devices, wherein the physical layer frame is transmitted at a datarate of 9.6 bits per second.
 24. The apparatus of claim 17, wherein thelength of the physical layer frame is 20 milliseconds (ms).
 25. Acomputer program product for managing wireless communication in amachine-to-machine (M2M) wireless Wide Area Network (WAN), the computerprogram product comprising a non-transitory computer-readable mediumstoring instructions executable by a processor to: generate a physicallayer frame for wireless M2M communication on a forward link in the M2Mwireless WAN, the frame comprising no more than three channels includinga first channel comprising a paging channel, and a second channelcomprising a traffic channel; perform a time division multiplexing (TDM)operation on one or more pilot symbols and one or more data symbols toobtain one or more TDM pilot bursts; scramble the TDM pilot bursts andthe data symbols using a first pseudo noise (PN) sequence, the first PNsequence being offset from a PN sequence used to scramble TDM pilotbursts and data symbols of a frame transmitted from a neighbor basestation; and insert the one or more TDM pilot busts in one or morechannels of the physical layer frame.
 26. The computer program productof claim 25, wherein the frame further includes a third channelcomprising an acknowledgment (ACK) channel, the length of the firstchannel comprising the paging channel and the length of the thirdchannel comprising the ACK channel is 5 milliseconds (ms), and thelength of the second channel comprising the traffic channel is 10 ms.27. The computer program product of claim 25, the computer-readablemedium storing instructions further executable by the processor to:transmit system information and timing information using the firstchannel comprising the paging channel.
 28. The computer program productof claim 25, the computer-readable medium storing instructions furtherexecutable by the processor to: identify a time slot of the physicallayer frame that is assigned to an M2M device; and transmit data duringthe identified time slot to the M2M device.
 29. The computer programproduct of claim 25, the computer-readable medium storing instructionsfurther executable by the processor to: receive a plurality of messagesfrom a plurality of M2M devices; generate a plurality of acknowledgment(ACK) messages; group the plurality of ACK messages into an ACK packet;and transmit the ACK packet comprising the plurality of ACK messages.30. The computer program product of claim 25, the computer-readablemedium storing instructions further executable by the processor to:insert the one or more TDM pilot bursts in each channel of the physicallayer frame, each TDM pilot burst comprising a length of 56 chips, achip being a pseudo noise (PN) code symbol; and space consecutive TDMpilot bursts by 256 chips.
 31. The computer program product of claim 25,the computer-readable medium storing instructions further executable bythe processor to: transmit the physical layer frame on the forward linkto one or more M2M devices, wherein the physical layer frame istransmitted at a data rate of 9.6 bits per second.
 32. The computerprogram product of claim 25, wherein the length of the physical layerframe is 20 milliseconds (ms).